Study On Indoor Radon And Its Daughters Based On Cluster

Radon is considered as the second largest reason of cause cancer,has been classed as one of 19 kinds main carcinogenic substances by the WHO;According to ICRP proposal and their own national conditions,building indoor radon protection standards has been set in many countries,our country promulgated Control standards of radon concentration in dwellings, Standard for controlling radon and its progenies in underground space and Radiological protection standards for using geothermal water in 1996 proceed from our national conditions,thus, it is meaningful to monitor and study of radon indoor, provide the foundation and dates for people to reduce radon concentration indoor.According to the Academic Divisions of the Chinese Academy of Sciences Pan Ziqiang's special report dates,the average concentration of radon indoor and outdoor in Fujian province are highest in China,it is important to study the distribution of radon indoor and make it clear how the daily radon concentration is changing in Fuzhou.We start with radon measuring instruments,compared with the results measured by RAD7,FT648 and activated carbon in the same radon concentration,we get a reduction formula between their experimental data.In order to study the distribution of radon concentration indoor, the finite element method and cluster theory were used to establish the model,and the distribution rule of radon concentration indoor and its influence factors were gained through the analysis of radon concentration model,after the concentration of radon located at different positions indoor measured by activated charcoal,we find that in the upper part of the room,radon concentrations are higher than the lower half and decreased with the distance to the wall expand,which are similar to the analysis of radon concentration distribution indoor model.The cumulative-sum method was used to measure radon exhalation rate from different walls and results are shown below: 0.8606×10-3Bq·m-2·s-1,2.274×10-3Bq·m-2·s-1,0.8606×10-3Bq·m-2·s-1,0.2714×10-3Bq·m-2·s-1, the floor is 0.5901×10-3Bq·m-2·s-1,the ceiling is2.044×10-3Bq·m-2·s-1. Radon equilibrium factor is found relate to ventilation,height,season and regional environment after measured by FT648 in different height and season in indoor and outdoor.Radon concentration daily changing rule experiments were carried on in a closed room locate at Fuzhou, and the radon concentration reach a maximum about at five o'clock in the morning and a minimum concentration about at six o'clock in the afternoon,which contrary to the temperature daily change regularity.